| AMCC suggested to set the PMU bit to 0 for best performace on the |
| PPC440 DDR controller. The 440er common DDR setup files (sdram.c & |
| spd_sdram.c) are changed accordingly. So all 440er boards using |
| these setup routines will automatically receive this performance |
| increase. |
| |
| Please see below some benchmarks done by AMCC to demonstrate this |
| performance changes: |
| |
| |
| ---------------------------------------- |
| SDRAM0_CFG0[PMU] = 1 (U-boot default for Bamboo, Yosemite and Yellowstone) |
| ---------------------------------------- |
| Stream benchmark results |
| ------------------------------------------------------------- |
| This system uses 8 bytes per DOUBLE PRECISION word. |
| ------------------------------------------------------------- |
| Array size = 2000000, Offset = 0 |
| Total memory required = 45.8 MB. |
| Each test is run 10 times, but only |
| the *best* time for each is used. |
| ------------------------------------------------------------- |
| Your clock granularity/precision appears to be 1 microseconds. |
| Each test below will take on the order of 112345 microseconds. |
| (= 112345 clock ticks) |
| Increase the size of the arrays if this shows that you are not getting |
| at least 20 clock ticks per test. |
| ------------------------------------------------------------- |
| WARNING -- The above is only a rough guideline. |
| For best results, please be sure you know the precision of your system |
| timer. |
| ------------------------------------------------------------- |
| Function Rate (MB/s) RMS time Min time Max time |
| Copy: 256.7683 0.1248 0.1246 0.1250 |
| Scale: 246.0157 0.1302 0.1301 0.1302 |
| Add: 255.0316 0.1883 0.1882 0.1885 |
| Triad: 253.1245 0.1897 0.1896 0.1899 |
| |
| |
| TTCP Benchmark Results |
| ttcp-t: socket |
| ttcp-t: connect |
| ttcp-t: buflen=8192, nbuf=2048, align=16384/0, port=5000 tcp -> |
| localhost |
| ttcp-t: 16777216 bytes in 0.28 real seconds = 454.29 Mbit/sec +++ |
| ttcp-t: 2048 I/O calls, msec/call = 0.14, calls/sec = 7268.57 |
| ttcp-t: 0.0user 0.1sys 0:00real 60% 0i+0d 0maxrss 0+2pf 3+1506csw |
| |
| ---------------------------------------- |
| SDRAM0_CFG0[PMU] = 0 (Suggested modification) |
| Setting PMU = 0 provides a noticeable performance improvement *2% to |
| 5% improvement in memory performance. |
| *Improves the Mbit/sec for TTCP benchmark by almost 76%. |
| ---------------------------------------- |
| Stream benchmark results |
| ------------------------------------------------------------- |
| This system uses 8 bytes per DOUBLE PRECISION word. |
| ------------------------------------------------------------- |
| Array size = 2000000, Offset = 0 |
| Total memory required = 45.8 MB. |
| Each test is run 10 times, but only |
| the *best* time for each is used. |
| ------------------------------------------------------------- |
| Your clock granularity/precision appears to be 1 microseconds. |
| Each test below will take on the order of 120066 microseconds. |
| (= 120066 clock ticks) |
| Increase the size of the arrays if this shows that you are not getting |
| at least 20 clock ticks per test. |
| ------------------------------------------------------------- |
| WARNING -- The above is only a rough guideline. |
| For best results, please be sure you know the precision of your system |
| timer. |
| ------------------------------------------------------------- |
| Function Rate (MB/s) RMS time Min time Max time |
| Copy: 262.5167 0.1221 0.1219 0.1223 |
| Scale: 258.4856 0.1238 0.1238 0.1240 |
| Add: 262.5404 0.1829 0.1828 0.1831 |
| Triad: 266.8594 0.1800 0.1799 0.1802 |
| |
| TTCP Benchmark Results |
| ttcp-t: socket |
| ttcp-t: connect |
| ttcp-t: buflen=8192, nbuf=2048, align=16384/0, port=5000 tcp -> |
| localhost |
| ttcp-t: 16777216 bytes in 0.16 real seconds = 804.06 Mbit/sec +++ |
| ttcp-t: 2048 I/O calls, msec/call = 0.08, calls/sec = 12864.89 |
| ttcp-t: 0.0user 0.0sys 0:00real 46% 0i+0d 0maxrss 0+2pf 120+1csw |
| |
| |
| 2006-07-28, Stefan Roese <sr@denx.de> |
